1. Technical Field
The invention generally relates to devices for insertion into a Eustachian tube. In particular, the invention relates to devices that include an insertable member, a means for immobilizing the device, a means for providing sufficient fluid communication between opposing surfaces of the insertable member to effect pressure equilibration therebetween, and to methods for using such devices.
2. Background Art
The Eustachian tube is a hollow lined tube that connects a middle ear to the nasopharynx. The middle ear portion of the tube can only be accessed by incising the eardrum or ear canal skin. The nasal portion of the tube is surrounded by cartilage that regulates opening and closing actions (torus tubarius). In its resting state, the Eustachian tube is in the closed position. Eustachian tube opening action is mediated by contraction of surrounding muscles that impinge upon the tube and torus tubarius. An opened tube ventilates and drains the middle ear and maintains proper pressure relationships among the eardrum, middle ear, and nasopharynx.
Eustachian tube dysfunction has been implicated in the development of various otologic diseases. The etiology of acute otitis media is hypothesized to be due to bacteria traveling into the middle ear from the nasal cavity in a setting of inflammation, which prevents the middle ear from draining properly. Chronic otitis media occurs when the Eustachian tube fails to ventilate the middle ear over an extended period. In these cases, fluid and thickened mucosa accumulate in the middle ear, causing hearing loss. As difficulty ventilating the middle ear continues, skin may become entrapped (cholesteatoma), and cause chronic infection and destruction of the ossicles, inner ear and mastoid air cell system.
Eustachian tube dysfunction is especially problematic for patients who are unable to clear their ears when flying and diving. In the setting of rapidly changing barometric conditions, as in flying and diving, inability to ventilate the middle ear sufficiently can lead to barotrauma with accumulation of fluid or blood in the middle ear. On occasion, Eustachian tube dysfunction patients can experience eardrum rupture, deep hearing loss and dizziness.
Treatment of Eustachian tube dysfunction has mainly been directed at ventilation of the middle ear via the eardrum or tympanic membrane. Typically, a myringotomy or incision through the substance of the eardrum is created, and a ventilation tube is placed within the incision. These ventilation tubes or grommets have been commercially available for over 50 years.
Such treatments are associated with numerous drawbacks. For example, ventilation tubes are typically spontaneous and uncontrollably extruded from the eardrum about 4-9 months after placement. The invasiveness of surgical procedures to the eardrum or tympanic membrane also represents a potential source of complications
Some long-term solutions have been proposed. U.S. Pat. No. 3,807,409 to Paparella et al. and U.S. Pat. No. 4,695,275 to Bruce et al. describe eardrum-based methods and modified ventilation tube flanges to promote lengthier tube retention periods. U.S. Pat. No. 3,982,545 to Silverstein and U.S. Pat. No. 5,047,053 to Jahn describe methods of ventilation tube insertion by modifying the ear canal. The materials used for ventilation tube construction for U.S. Pat. No. 3,982,545 is silicone and U.S. Pat. No. 5,047,053 is biointegratable hydroxyapatite. These prostheses may be extruded at variable times and require complex office or operating room procedures to clear debris that surrounds the ventilation tubes.
Direct stenting of the Eustachian tube through the middle ear orifice have been proposed. Devices for carrying out such Eustachian tube stenting have been described, for example, in U.S. Pat. No. 4,015,607 to Wright, III, U.S. Pat. No. 6,589,286 to Litner and PCT/JP2005/020014. As a short-term solution, Litner describes an elongated, drug-eluting stent designed to be secured at the tympanic orifice as a short-term solution to maintain the patency of the Eustachian tube. In contrast, the Wright apparatus is designed as a long-term solution. Long-term Eustachian tube stenting via the middle ear have resulted in unplanned tube extrusion, mucosal inflammation of the Eustachian tube and blockage. In any case, these apparatuses are placed through either a myringotomy or incision into the ear canal.
Myringotomy can lead to persistent abnormalities with the eardrum. In the pediatric age group where myringotomy with ventilation tube insertion is a common procedure, the most concerning complication is permanent eardrum perforation. When eardrums heal after myringotomy, many are clearly abnormal, such as, formation of retraction pockets, thin atrophic membranes, and tympanosclerosis. The impact of these undesirable changes is hearing loss that ranges from 3-5 decibels (dB). Incision into the ear canal is a more technically complex surgical process. Bleeding in the ear canal and scarring of the eardrum are common outcomes.
While previous methods of relieving Eustachian tube dysfunction and associated problems have been focused on the middle ear component, there is recent indication that treatment at the nasopharynx component is promising. A successful method and apparatus for the treatment of Eustachian tube dysfunction at the torus tubarius location would be free of undesirable outcomes associated with eardrum and ear canal based surgical procedures. Poe et al. (2003), “Laser Eustachian Tuboplasty: A Preliminary Report,” LARYNGOSCOPE, 113(4):583-91, describes a surgical procedure which involves partial excision of the cartilaginous portion of the torus tubarius to increase the opening size. This surgical procedure has been effective in preventing the need to replace ventilation tubes in 70% of patients with chronic otitis media.
A non-surgical device that acts to enlarge the torus tubarius aperture on a temporary basis appears to be effective in chronic otititis media. The EarPopper™ delivers a pressure controlled constant volume velocity of air through the nose to the Eustachian tube orifice in the nasopharynx. As disclosed in Arick et al. (2005), “Nonsurgical home treatment of middle ear effusion and associate hearing loss in children. Part I: Clinical trial,” EAR, NOSE, THROAT JOURNAL, 85(10):1-13, such a device has been used to restore hearing to normal in 85% of patients without antibiotics or ventilation tubes over 7 weeks.
Nevertheless, opportunities exist to overcome disadvantages associated with known technologies associated with the treatment of disorders associated with an obstructed Eustachian tube.